JPH0695366B2 - Repositioning device for streaming magnetic tape device - Google Patents

Description

The present invention relates to a repositioning device for a streaming magnetic tape device.

<Prior Art> Conventionally, a magnetic tape device used as an external storage device of a computer is conventionally provided with a capstan motor in addition to a reel motor, and the tape running is controlled by the capstan motor, so that the tape running during tape running is For each data block, the start-stop method was used in which the tape running is temporarily stopped at the blank part (interblock cap: IBG) between the data block and the adjacent data block.

However, in recent years, the capstan motor has been omitted due to the demand for high-speed tape running and cost reduction.
A system (that is, a streaming system) in which tape traveling is directly controlled by a reel motor and tapes are continuously traveling without stopping traveling in an IBG is widely used.

However, in such a streaming magnetic tape device in which the tape is directly driven by the reel motor instead of the capstan motor, when the tape running needs to be stopped by the IBG during the running (for example, a command from the host device is delayed). If the magnetic tape can no longer keep streaming, or if the written data is incorrect, etc., the reel inertia and IBG distance are short even if you try to stop it with the IBG. (Normal
0.6 inch), so it cannot stop at the IBG and passes through the IBG until it reaches another data block and then stops. Therefore, in order to run the tape again, the original IBG
The operation of returning the tape to the midpoint of, that is, the repositioning operation is required.

Then, in the conventional streaming magnetic tape device,
The repositioning operation is performed based on the principle shown in FIG. 6 based on the tape position information from the tachometer provided in the tape running system.

In FIG. 6, 1 is a tape, BOT is the start end of tape 1, E
OT is the end. B _N is the N-th data block counting from BOT of the tape 1, B N _{+ 1} (N + 1) -th data block, I _N is the N-th IBG from BOT, horizontal axis X tape position where the tape is positioned at the magnetic head, The Y-axis is the positive direction above the X-axis (the direction in which the tape 1 is wound on the BOT side)
Tape running speed, downward tape running speed in the opposite direction,
Y ₀ represents a tape traveling speed of zero (that is, the tape stops), Y ₁ represents a tape traveling speed at a constant speed in the forward direction, and Y ₂ represents a tape traveling speed at a constant speed in the reverse direction (for example, Y ₁ = Y ₂ Is).

That is, as shown in FIG. 6, the tape 1 while traveling at constant speed Y ₁ in the forward direction by the streaming travel, the midpoint of the N-th IBG past the N-th data block B _N (i.e. I _N) When it comes to A, it is assumed that a stop signal is sent to the reel motor in order to stop it. However, because of the inertia of the reel, immediately can not be stopped, the tape 1 is stopped reaches progressively until decelerated point past the I _N with B.

The tape running distance from the point A at which the tape running stop command is output to the point B at which the tape running is stopped is measured with, for example, a tachometer. That is, this tachometer is composed of, for example, a light emitting element, a light receiving element, and a rotating body that makes frictional contact with a tape having slits provided between these elements. The light receiving element outputs a pulse each time the light from the light emitting element passes through the slit of the rotating body and is received. The output pulse is supplied to, for example, an up / down counter, and the output pulse number Is counted in the up direction to measure the tape running distance.

Then, the reel 1 drives the tape 1 to run in the opposite direction. Also in this case, due to the inertia of the reel, the tape 1 does not reach the constant speed Y ₂ immediately, but gradually increases in speed at the point C.
Reach Y ₂ . After reaching the constant speed Y ₂ , a stop signal is output to the reel motor at point D after a predetermined time. Due to the inertia of the reel, the tape 1 likewise gradually decelerates and stops at point E. The output pulse of the tachometer from the point B to the point C, the point D, and the stop at the point E is counted in the down direction by the up / down counter. The counter is minus as much as the counts of B point → C point → D point → E point exceed the count number of A point → B point.

Next, the tape 1 is run in the forward direction. Similarly, the tape 1 gradually increases in speed to reach the constant speed Y ₁ at the point F. From point E, tachometer output pulses are counted in the up direction. Then, it is considered that the point G at which the minus amount of the up / down counter becomes zero after reaching the point E from the point E coincides with the original position A where the first tape running stop command is output. Therefore, at this G point, the operation of returning to the original position, that is,
Since the repositioning operation is completed, the tape 1 continues to run in the positive direction at the constant speed Y ₁ , and the reading and writing of the next data block B _{N + 1 and the} like are performed.

<Problems to be Solved by the Invention> However, in such a conventional repositioning device for a streaming magnetic tape device, slips between the rotating body of the tachometer and the tape, miscounting of the output pulse of the tachometer, etc. are directly caused by the tachometer. It causes an error in tape position detection.

Therefore, since these errors are accumulated during a long distance of A point → B point → C point → D point → E point → F point → G point, the original value at the start of counting of the up / down counter is The tape position A and the tape position G when the minus amount of the count becomes zero do not always match.

Therefore, counting tape position G when the negative component becomes zero of the count at the start of the tape position, i.e. out of the N-th IBG (I _N), to the point G before the data block B _N Take or next data block B
_The situation related to _{N + 1} often occurred. For this reason, you may accidentally erase the correct data block before and after,
Malfunctions such as starting reading from the middle of the preceding and following data blocks often occur.

The present invention eliminates such drawbacks and ensures that even if slip between the tape and the tachometer, miscounting of the output pulse of the tachometer, etc. occurs, the correct data can be repositioned to the correct position regardless of this, and correct data can be obtained. It is an object of the present invention to provide a repositioning device for a streaming magnetic tape device, which is capable of reading and writing.

<Means for Solving the Problem> In order to solve this problem, the present invention provides, as shown in FIG. 1, (a) a traveling distance measuring means (20) for measuring a traveling distance of a magnetic tape; (B) a tape stop detection means (30) for detecting the stop of the running of the magnetic tape and outputting a stop detection signal, and (c) a front end edge and a rear end edge of a data block recorded on the magnetic tape. Data block edge detection means (40) for detecting and outputting a front edge detection signal and a rear edge detection signal, and (d) it operates when a repositioning command is received from the outside, and the repositioning command is issued. In response to the received predetermined edge detection signal from the data block edge detection means within a predetermined time before and after the reception, a drive stop command is given to the reel motor and the traveling distance is It gives a measurement start command to the constant means to start measurement of the first travel distance,
Then, in response to the supply of the stop detection signal from the tape stop detection means, a reverse rotation drive command is given to the reel motor and a tape travel distance measurement start command in the reverse direction is given to the travel distance measurement means. Of the first distance measured by the mileage measuring means.
When the mileage of the vehicle and the second mileage become equal, the repositioning operation is normally performed in response to the supply of a predetermined edge detection signal from the data block edge detection means within a predetermined time before and after that. And a control means (10) for outputting a first notification signal for notifying that the operation is being performed.

<Operation> When a repositioning command signal is given from a main control device such as a host computer, the control means has a front edge detection signal or a rear edge detection signal from the data block edge detection means within a predetermined time before and after that. When you receive
A drive stop command for the reel motor is output and a measurement start command is given to the traveling distance measuring means. After that, when the stop detection signal is received from the tape stop detection means, the control means outputs the reverse rotation drive command to the reel motor and
An instruction to start measuring the tape traveling distance in the opposite direction is given to the traveling distance measuring means. Then, when the tape running distance in the forward direction and the tape running distance in the reverse direction measured by the running distance measuring means become equal to each other, the control means outputs the front edge detection signal from the data block edge detecting means within a predetermined time thereafter. Alternatively, when the trailing edge detection signal is received, a signal indicating this is output to the main controller. Therefore, if this signal is not supplied from the control means, if the main controller is set so as not to read or write data, the correct data block before and after will be erased, or the data block before and after will be erased. It becomes possible to prevent malfunctions such as starting reading from.

<Example> An example of the present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration, and the control means 10 gives a measurement start command to the running distance measuring means 20 and controls the rotation of a reel motor (not shown) for running the magnetic tape. Upon receipt of the measurement start command, the traveling distance measuring means 20 starts measuring the traveling distance of the magnetic tape (not shown) and outputs the measurement result to the control means 10. The tape stop detection means 30 outputs a stop detection signal to the control means 10 when detecting the stop of the running of the magnetic tape, that is, the stop of the reel motor for running the magnetic tape. The data block edge detection means 40 outputs a front edge detection signal or a rear edge detection signal when detecting the front edge or the rear edge of the data block recorded on the magnetic tape.

When a repositioning command signal is given from a main control device such as a host computer (not shown), the control means 10 has the data block within a predetermined time before and after the repositioning command signal.
When the front edge detection signal or the rear edge detection signal is received from the edge detection means 40, a drive stop command for the reel motor is output and a measurement start command is given to the travel distance measurement means 20. After that, when receiving the stop detection signal from the tape stop detection means 30, the control means 10
While outputting a reverse drive command to the reel motor,
A command to start measuring the tape traveling distance in the reverse direction is given to the traveling distance measuring means 20. Then, the control means (10), when the tape running distance in the forward direction and the tape running distance in the reverse direction measured by the running distance measuring means (20) become equal, then the data block edge detecting means within a predetermined time. When it receives the leading edge detection signal or the trailing edge detection signal from 40, it outputs a signal to that effect to the main controller.

Therefore, when this signal is not supplied from the control means 10, if the main controller is set so as not to read or write data, the correct data block before and after is erased, It becomes possible to prevent malfunction such as starting reading from the middle of the block.

FIG. 2 shows the above configuration in more detail. The control means 10 includes a zero detection circuit 12, a control circuit 14, and a coincidence confirmation circuit.
It consists of 16. The mileage measuring means 20 is a tachometer 22.
And a mileage measuring device 24. The tape stop detection means 30 includes the tachometer 22 and the tape stop detection device 32. The data block edge detection means 40
Is a magnetic head 42 and a data block edge detector
It consists of 44 and. In the figure, 50 is digital /
A motor drive control circuit including an analog converter 52 and a servo amplifier 54, and 60 is a reel motor for running the tape.

That is, the running distance of the magnetic tape is measured by using the tachometer 22 provided in the running system of the tape. The tachometer 22 includes, for example, a light emitting element, a light receiving element, and a rotating body that makes frictional contact with a tape having slits provided between these elements. The element produces a pulse output each time the light from the light emitting element passes through the slit of the rotating body and is received. The output pulse of the tachometer 22 is measured by the mileage measuring device 24. This mileage measuring device
Reference numeral 24 is, for example, an up / down counter, which counts the output pulse of the tachometer 22 in the up direction when the tape is running in the forward direction and in the down direction when the tape is running in the reverse direction. To do. The output pulse of the tachometer 22 is also supplied to the tape stop detection device 32. The tape stop detection device 32 outputs a stop detection signal when the output pulse of the tachometer 22 does not occur.

The magnetic head 42 reads and writes the data blocks recorded on the magnetic tape. The data block edge detection device 44 detects the leading edge and the trailing edge of the data block by the read signal amplifier 46 that amplifies the output signal of the magnetic head 42 and the amplified output signal of the magnetic head 42. In addition, the data block detection circuit 48 outputs a front edge detection signal and a rear edge detection signal. The data block detection circuit 48 is supplied with a signal indicating the tape running direction from the control circuit 14, and therefore it is known whether the detected data block edge is the leading edge or the trailing edge. It is like this.

When the count value output of the mileage measuring device (up / down counter) 24 becomes zero, the zero detection circuit 12 detects this and outputs a zero detection signal to the control circuit 14 and the coincidence confirmation circuit 16. The control circuit 14 controls the repositioner, and starts a control operation described later in response to a repositioning command a from an external main control device while the tape is running. The coincidence confirmation circuit 16 receives the front edge signal or the rear edge signal from the data block edge detection device 44 within a predetermined time before and after receiving the zero detection signal from the zero detection circuit 12, and outputs a coincidence signal. b is output to the main controller. Therefore, the main controller can know that there is an error in the repositioning operation when the coincidence signal b is not supplied, and the main controller can read or write data at that time. By setting in advance not to perform, it is possible to prevent malfunctions such as erasing the correct data block and starting reading from the middle of the preceding and following data blocks.

This operation will be described in more detail with reference to FIGS. 3, 4 (a) and 4 (b).

In FIG. 3, 70 is a magnetic tape, BOT is the start end of the tape 70, and EOT is the end end of the tape 70. B _N is the N-th data block as counted from the BOT of the tape 70, B N _+
1 N + 1 th data block, _{I N} is N from BOT
Represents the second IBG, E ₁ represents the leading edge of the data block, and E ₂ represents the trailing edge. The horizontal axis X represents the tape position where the tape 70 is located on the magnetic head 42, and the Y-axis is the tape running speed in the positive direction (the direction in which the tape 70 is wound on the BOT side) above the X-axis and the reverse direction in the lower direction. It represents the running speed of the tape. Y ₀ represents a tape running speed of zero (that is, the tape stops), Y ₁ represents a tape running speed of a constant speed in the positive direction, and Y ₂ represents a tape running speed of a constant speed in the reverse direction (however, for example, Y ₁ = Y ₂ ).

Normally, the tape 70 is continuously run in the positive direction by controlling the motor drive control circuit 50 by the main controller (not shown), and the magnetic head 42 reads or writes a data block. Has been.

Here, as shown in Figure 3, when A has passed, for example, N-th data block B _N of the tape 70, repositioning command a is assumed to be supplied from the main controller.
Since this point A is within IBG (I _N), in the flowchart of FIG. 4, data block edge detector
At 44, the trailing edge E ₂ is detected, the trailing edge detection signal is supplied (step 401), and is within the first predetermined time t ₁ (corresponding to the IBG distance) (step 402). . If a repositioning command is given at this point A (step
402), the control circuit 14 includes a first motor drive control circuit 50.
At the same time as outputting the traveling stop command signal for the second time,
A first measurement start command signal for starting counting in the up direction is output to the down counter 24 (step 403). Tape 70
Is the inertia of the reel, is gradually decelerated as shown in FIG. 3, and stops at the point B past the IBG (I _N). The running distance of the tape 70 from the point A to the stop at the point B is measured by counting the output pulse from the tachometer 22 by the up / down counter 24.

When the tape 70 stops running, no output pulse is generated from the tachometer 22, so the tape stop detection device 32 detects this and outputs a first tape stop detection signal to the control circuit 14.

When the control circuit 14 receives the first tape stop detection signal (step 404), the control circuit 14 sends a backward running command signal to the reel motor 60 via the motor drive control circuit 50, and
A second measurement start command signal for starting the counting operation in the down direction is sent to the up / down counter 24 (step 40
Five). The tape 70 gradually increases in speed as shown in FIG. 3 due to the inertia of the reel, and becomes constant at point C. During this time, the output pulse from the tachometer 22 is counted down by the up / down counter 24. Therefore, the count value counted from the point A to the point B is subtracted,
The distance from point A to point B is almost equal to the distance from point B to point C, and it becomes zero at point C.

Even if a slip between the tape 70 and the rotating body of the tachometer 22 or a miscount of the output pulse of the up / down counter 24 occurs, the distances from point A to point B and point B to point C are both extremely short. The point C at which the count value of the up / down counter 24 becomes zero is near the point A, and IBG (I
_N ).

When the count value of the up / down counter 24 becomes zero, the first zero detection signal is sent from the zero detection circuit 12 to the control circuit 14 and the coincidence confirmation circuit 16. The reverse running of the tape 70 continues at the constant speed Y ₂ . Data block edge detector 44
Receives a trailing edge (E ₂ ) detection signal based on the output of the magnetic head 42. This trailing edge detection signal (for example,
When it is received within the second predetermined time t ₂ (corresponding to the IBG distance) (step 406), the coincidence confirmation circuit 16 confirms the first coincidence and sends the first coincidence signal b to the main controller. Output (step 407). When the first coincidence signal b is not supplied, the main control unit determines that the error occurs when the point C hits the data block, the repositioning operation is stopped, and a warning sound is generated. Notify the user.

When the first coincidence signal b is supplied, the main controller further continues the repositioning operation.
That is, the control circuit 14 causes the tape 70 to continue traveling at a constant speed in the reverse direction. In leading edge E ₁ of the data block B _N, the data block edge detector 44 detects the leading edge E _1, and outputs a leading edge detection signal to the control circuit 14 (step 408), the control circuit 14 ( For example, 1 / the distance of IBG
After the elapse of a _third predetermined time t _{3 (} corresponding to 2), that is, at the point D, the second drive stop command signal is output to the motor drive control circuit 50 and the up / down counter 24 starts the third measurement. A command signal is output to start the counting operation in the down direction (step 409). The tape 70 decelerates gradually from the point D due to the inertia of the reel and stops at the point E. During this time, the output pulse of the tachometer 22 from the point D to the point E is counted by the up / down counter 24 from zero to the down direction. When the tape 70 stops at point E, the tape stop detection device 32 outputs a second tape stop detection signal to the control circuit 14.

When this second tape stop detection signal is received (step
410), the control circuit 14 outputs a forward drive command signal for the reel motor 60 to the motor drive control circuit 50, and at the same time sends a fourth measurement start command signal to the up / down counter 24 so that Start counting operation (step 41
1). Due to the inertia of the reel, the tape 70 gradually increases in speed as shown in FIG. 3 and becomes constant at point F. During this time, the output pulse from the tachometer 22 is counted by the up / down counter 24 in the up direction. Therefore, the distance becomes almost equal to the distance from the point D to the point E and becomes approximately zero at the point from the point E to the point F.

When the count value of the up / down counter 24 becomes zero, the second zero detection signal is sent from the zero detection circuit 12 to the control circuit 14 and the coincidence confirmation circuit 16. The tape 70 continues traveling in the positive direction at the constant speed Y ₁ .

Similarly to the above, even if the slip between the tape 70 and the rotating body of the tachometer 22 and the miscount of the output pulse of the up / down counter 24 occur, the point D → the point E and the point E → the point F
Since the distances between the points are both extremely short, the point F at which the count value of the up / down counter 24 becomes zero is located in the vicinity of point F and within IBG (IN _-1 ).

When past the point F the forward direction traveling directly through the N-th data block B _N magnetic head 42, the data block from the edge detector 44 N-th data block B _N leading edge of the (E ₁ ) Detection signal match circuit 16
Is output to. When this front edge detection signal is received within the fourth predetermined time t ₄ (for example, corresponding to the IBG distance) after receiving the zero detection signal (step 412), the coincidence confirmation circuit 16
Confirms the second match and outputs the second match signal b to the main controller (step 413). If the second coincidence signal b is not supplied, the main control unit F
As an error that a dot is applied to a data block, the repositioning operation is stopped and a warning sound is generated to notify the user of the error.

Then the tape 70 runs further and the trailing edge (E ₂ )
When the detection signal is output to the match confirmation circuit 16 (step 41
4) Then, the coincidence confirmation circuit 16 further outputs a third coincidence signal b to the main controller in order to inform that the repositioning is completed (step 415). As a result, the repositioning operation is completed, and thereafter, the motor drive control circuit 50 is controlled by the main controller as it is to read or write the next data block B _{N + 1} .

In this way, since the error detection is performed twice by comparing the count values over an extremely short distance, reliable repositioning can be performed. Further, to perform repositioning, previous data block B _N of IBG (I _N) by the magnetic head 42
Once passed through the tape 70 to the confirmed while backward, then forward direction by traveling, it is so arranged to pass to confirm the magnetic head 42 again the same data block B _N, reliably N th It is guaranteed to be repositioned to the intermediate IBG (I _N ) of the data block B _N of the following and the next data block B _{N + 1} .

Next, the repositioning command a is the Nth IBG.
A case will be described in which the data is supplied immediately after entering the next data block B _{N +} 1 beyond ( _IN ).
That is, if the repositioning command a is supplied within the fifth predetermined time t ₅ (for example, corresponding to the IBG distance + α) after receiving the trailing edge detection signal (step 416),
As shown in steps 403 to 405, the position at the time when the tape is driven and the speed becomes constant again becomes close to the position (distance of IBG + α) at the time of receiving the repositioning command a. Then, as shown in steps 406 and 407, the first coincidence signal b is output to the main controller. However, in this case, the second predetermined time t ₂ is equal to the _fifth predetermined time t ₅
It is a time to sufficiently cover + α minutes in. The subsequent steps are the same as the above steps 408 and after.

If the repositioning command a is supplied immediately before the end of the _Nth data block BN,
After receiving the repositioning command a (step 417),
It continued constant speed running until the trailing edge E ₂ of the data block B _N is detected with a sixth predetermined time t within ₆ (step 41
8), after the trailing edge detection signal is supplied from the data block edge detector 44, and after the lapse of a _seventh predetermined time t ₇ (corresponding to, for example, 1/2 of the IBG distance) (step 41
9), proceed to step 403 above.

FIG. 5 is a flow chart showing an operation example when the repositioning start position is not based on the rear end edge E ₂ as described above but based on the front end edge E ₁ . That is, when the repositioning command a is supplied to the point in the I _N has not yet been detected leading edge E ₁ (step 501). Therefore, if the repositioning command a is supplied at this point (step 502), the constant speed traveling in the forward direction is continued until the front edge E ₁ is detected. If the edge E ₁ is detected within the eighth predetermined time t ₈ (corresponding to the IBG distance, for example) (step 503), the process proceeds to step 403 shown in FIG. 4 (a). If so, the repositioning operation similar to that of the above-described embodiment can be performed.

The same applies if the repositioning command a is supplied to the time just before the I _N. However, in this case, the eighth predetermined time t ₈ is a time corresponding to the IBG distance + α.

Further, when the repositioning command a is supplied to a point in time immediately after the I _N proceeds from step 501 of FIG. 5 in step 504. That is, after the front edge E ₁ is detected (step 50
1), repositioning command a within the 9th predetermined time t ₉
Repositioning is performed only when is supplied (step 502).

Instead of detecting the trailing edge E ₂ of step 406,
As shown in step 406 ′ in FIG. 4 (c), the front edge E
_Even if it operates according to the detection of ₁ , the same effect can be obtained.

<Effects of the Invention> As described above, in the present invention, the device for measuring the tape running distance is merely used as a rough guide for tape positioning, and the actual data block edge recognition is performed based on the magnetic head signal. Since the repositioning is performed in-line, even if a slip between the tachometer's rotating body and the tape or a miscount of the output pulse of the tachometer occurs, it can be returned to the original IBG without fail. Therefore, you can accidentally delete data as in the past,
It is possible to eliminate malfunctions such as starting reading data from the middle of a data block.

[Brief description of drawings]

FIG. 1 is a block configuration diagram showing a schematic configuration of a repositioner of a streaming magnetic tape device of the present invention, FIG. 2 is a more detailed block configuration diagram of the repositioner of FIG. 1, and FIG. 3 is for explaining a repositioning operation. 4A, FIG. 4A and FIG. 4B are flow charts for explaining the operation of the repositioning controller of FIG. 2, and FIG. 4C is a flow chart of FIG. 4A. A modified example of step 406, FIG. 5 is a flow chart for explaining another example of the operation of the repositioning control unit in FIG. FIG. 6 is a diagram for explaining the operation of the conventional repositioning device. 10 ... Control means, 12 ... Zero detection device, 14 ... Control circuit,
16 …… Matching confirmation circuit, 20 …… Distance measuring means, 22 ……
Tachometer, 24 ... Odometer, 30 ... Tape stop detector, 32 ... Tape stop detector, 40 ... Data block edge detector, 42 ... Magnetic head, 48 ...
… Data block detection circuit, 50… Motor drive control circuit, 60… Reel motor, 70… Tape.

Claims (1)

[Claims] 1. A repositioning device of a streaming magnetic tape device for writing or reading data by running a magnetic tape by a reel motor, and a running distance measuring means for measuring a running distance of the magnetic tape. A tape stop detecting means for detecting a stop of the running of the magnetic tape and outputting a stop detection signal, and detecting a front edge or a rear edge of a data block recorded on the magnetic tape to detect a front edge detection signal. Or a data block for outputting the trailing edge detection signal
Edge detection means, which operates when receiving a repositioning command from the outside, according to the supply of a predetermined edge detection signal from the data block edge detection means within a predetermined time before and after receiving the repositioning command, A drive stop command is given to the reel motor and a measurement start command is given to the running distance measuring means to start the measurement of the first running distance, and then a stop detection signal is supplied from the tape stop detecting means. Then, a reverse drive command is given to the reel motor and a tape running distance measurement start command in the reverse direction is given to the running distance measuring means to start the second running distance measurement, and the running distance measuring means measures the distance. From the data block edge detection means within a predetermined time before and after the first traveled distance and the second traveled distance are equalized. A streaming magnetic tape device comprising: a control unit that outputs a first notification signal to the outside that notifies that the repositioning operation is normally performed in response to the supply of a predetermined edge detection signal. Repositioning device.